U.S. patent application number 13/435603 was filed with the patent office on 2013-10-03 for glass fiber composite material for electrical insulation.
This patent application is currently assigned to ABB TECHNOLOGY AG. The applicant listed for this patent is Thomas A. Hartmann, Joel A. Kern, Samuel S. Outten. Invention is credited to Thomas A. Hartmann, Joel A. Kern, Samuel S. Outten.
Application Number | 20130257214 13/435603 |
Document ID | / |
Family ID | 49233958 |
Filed Date | 2013-10-03 |
United States Patent
Application |
20130257214 |
Kind Code |
A1 |
Kern; Joel A. ; et
al. |
October 3, 2013 |
GLASS FIBER COMPOSITE MATERIAL FOR ELECTRICAL INSULATION
Abstract
A composite electrical insulation material is comprised of
first, second and third layers. The first and third layers are
glass fiber mat and the second layer is a thin film material. The
first and third layers are bonded to the second layer using a thin
resin solution. The insulation is used in electrical machines such
as transformers, generators, and motors. The insulation serves as a
high/low barrier, high voltage conductor wrap, and low voltage
sheet insulation in transformers. In generators and motors, the
insulation serves as wrap for conductor windings and wedge
insulation for stator and rotor assemblies.
Inventors: |
Kern; Joel A.; (Wytheville,
VA) ; Hartmann; Thomas A.; (Wytheville, VA) ;
Outten; Samuel S.; (Wytheville, VA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kern; Joel A.
Hartmann; Thomas A.
Outten; Samuel S. |
Wytheville
Wytheville
Wytheville |
VA
VA
VA |
US
US
US |
|
|
Assignee: |
ABB TECHNOLOGY AG
Zurich
CH
|
Family ID: |
49233958 |
Appl. No.: |
13/435603 |
Filed: |
March 30, 2012 |
Current U.S.
Class: |
310/179 ;
174/137R; 336/220 |
Current CPC
Class: |
H02K 3/30 20130101; H01F
38/18 20130101; H02K 3/34 20130101; H01F 27/324 20130101 |
Class at
Publication: |
310/179 ;
174/137.R; 336/220 |
International
Class: |
H02K 3/34 20060101
H02K003/34; H01F 27/28 20060101 H01F027/28; H01B 17/00 20060101
H01B017/00 |
Claims
1. A composite insulation material for an electrical machine
selected from the group consisting of a transformer, generator and
motor, said composite insulation comprised of first and third
layers of glass fiber mat, a second layer of a thin film bonded to
said first and third layers, at least one of said first and third
layers in contact with a conductor of said electrical machine.
2. The composite insulation of claim 1 wherein said second layer is
selected from the group consisting of polyethylene naphthalate
film, polyethylene terephthalate film, aramid paper, aramid fiber,
polyester fiber, polyester film, polyetheretherketone, polyimide
film, and poly(meta-phenyleneisophthalamide).
3. The composite insulation of claim 1 wherein said second layer is
bonded to said first and third layers, respectively, by a
polyesterimide solution.
4. A transformer comprising: a ferromagnetic core having at least
one core leg; and a coil assembly mounted to said at least one core
leg, said coil assembly comprising: a low voltage coil winding, a
high voltage coil winding, and a high/low barrier disposed between
said high and low voltage coil windings, said high/low barrier
formed from a composite material having at least three layers, said
composite material comprised of first and third layers of glass
fiber and a second layer of a thin film material, said first layer
in contact with said low voltage coil winding and said third layer
in contact with said high voltage coil winding.
5. The transformer of claim 4 wherein said second layer is selected
from the group consisting of polyethylene naphthalate film,
polyethylene terephthalate film, aramid paper, aramid fiber,
polyester fiber, polyester film, polyetheretherketone, polyimide
film, and poly(meta-phenyleneisophthalamide).
6. The transformer of claim 4 wherein said second layer is bonded
to said first and third layers using a polyesterimide solution.
7. A transformer coil winding, having composite insulation
sandwiched between successive layers of sheet conductor, said
composite insulation having first, second, and third layers, said
first and third layers formed of a glass fiber and in contact with
said successive conductor layers, and said second layer formed of a
thin film and disposed between said first and third layer.
8. The composite insulation of claim 7 wherein said second layer is
selected from the group consisting of polyethylene naphthalate
film, polyethylene terephthalate film, aramid paper, aramid fiber,
polyester fiber, polyester film, polyetheretherketone, polyimide
film, and poly(meta-phenyleneisophthalamide).
9. An electrical machine having at least one winding formed of a
conductor wire, said electrical machine selected from the group
consisting of a transformer, generator and motor, said conductor
wire encompassed by composite insulation, said composite insulation
comprised of a first and third layer of glass fiber and a second
layer comprised of a thin film, said composite insulation
surrounding an entire outside surface of said conductor wire.
10. The electrical machine of claim 9 wherein said thin film is
selected from the group consisting of polyethylene naphthalate
film, polyethylene terephthalate film, aramid paper, aramid fiber,
polyester fiber, polyester film, polyetheretherketone, polyimide
film, or poly(meta-phenyleneisophthalamide).
Description
FIELD OF INVENTION
[0001] The present application is directed to a glass fiber
composite material for use as insulation in electrical
machines.
BACKGROUND
[0002] Insulation is used in electrical applications such as
transformers, motors and generators to provide withstand to high
AC, DC, or transient voltages (such as impulse voltage) at high
operating temperatures. Insulation materials such as inorganic
clays, aramid papers, polyimide films, and polyester films, as well
as composites of those materials have been used as insulation in
transformers, electric motors and generators.
SUMMARY
[0003] A composite insulation material for an electrical machine
has first and third layers formed from a glass fiber mat and a
second layer of a thin film bonded to said first and third layers.
At least one of the first and third layers is in contact with a
conductor of the electrical machine.
[0004] A transformer utilizing the composite insulation material
has a ferromagnetic core having at least one core leg and a coil
assembly mounted to the at least one core leg. Further, the coil
assembly is formed of a low voltage coil winding, a high voltage
coil winding, and a high/low barrier located between the high and
low voltage coil windings. The high/low barrier is formed from a
composite material having at least three layers. The first and
third layers are a glass fiber and the second layer is a thin film
material. The first layer is in contact with the low voltage coil
winding and the third layer is in contact with the high voltage
coil winding.
[0005] A transformer coil winding has composite insulation
sandwiched between successive layers of sheet conductor. The
composite insulation has first and third layers formed of a glass
fiber and in contact with said successive conductor layers, and a
second layer formed of a thin film between the first and third
layers.
[0006] An electrical machine such as a transformer, generator or
motor, has at least one winding formed of a conductor wire. The
conductor wire is encompassed by composite insulation. The
composite insulation is comprised of a first and third layer of
glass fiber and a second layer comprised of a thin film. The
composite insulation surrounds an entire outside surface of said
conductor wire.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] In the accompanying drawings, structural embodiments are
illustrated that, together with the detailed description provided
below, describe exemplary embodiments of a composite insulation
material for electrical applications. One of ordinary skill in the
art will appreciate that a component may be designed as multiple
components or that multiple components may be designed as a single
component.
[0008] Further, in the accompanying drawings and description that
follow, like parts are indicated throughout the drawings and
written description with the same reference numerals, respectively.
The figures are not drawn to scale and the proportions of certain
parts have been exaggerated for convenience of illustration.
[0009] FIG. 1 shows a perspective view of a section of a sheet of
composite insulation embodied in accordance with the present
invention;
[0010] FIG. 2 shows an exemplary coil assembly having an insulating
high/low barrier formed from the sheet of composite insulation;
and
[0011] FIG. 3 is an exploded view of stator and rotor assemblies in
an exemplary motor, showing the utilization of the composite
insulation in an exemplary embodiment of the present invention.
DETAILED DESCRIPTION
[0012] With reference to FIG. 1, a multi-layer sheet of composite
electrical insulation material 50 (herein after composite
insulation 50) is depicted. Although the composite insulation 50 is
depicted as having three layers, the composite insulation 50 may be
embodied as two, three, four or more layers, depending on the
application.
[0013] An embodiment of the composite insulation 50 having two
layers is formed of a first layer 10 of a glass fiber mat and a
second layer 20 of polyethylene naphthalate or another material
suitable for the application as described below. An embodiment of
the composite insulation 50 having three layers is formed from
first and third layers 10, 30 of a glass fiber material and a
second layer 20 of polyethylene napthalate film sandwiched between
said first and third layers 10, 30. Alternatively, the composite
insulation 50 may be embodied as four layers, having an outside
layer of glass fiber material on opposing sides of a double layer
of polyethylene napththalate.
[0014] The composite insulation 50 has applications in various
electrical devices and machines including but not limited to
motors, transformers, and generators. The composite insulation 50
was developed to protect electrical machines from thermal and
dielectric stresses in systems having ratings of from about 0 Volts
to about 1,000 Volts such as general purpose transformers and
induction motors as well as dry-type distribution transformers
having ratings of from about 1,000 Volts to about 34,500 Volts.
[0015] A preferred embodiment of the composite insulation 50 is
comprised of at least three layers. The first and third layers 10,
30 are comprised of a sheet of glass fiber mat or other suitable
glass fiber material. The thickness of the first and third layers
10, 30 is from about 0.025 mm to about 0.26 mm. An example of a
glass fiber mat that is suitable for the application is
Advantex.RTM. E-CR glass, available from Owens Corning Composite
Materials of Toledo, Ohio.
[0016] A second layer 20 of the composite insulation 50 is
comprised of a film sheet of polyethylene naphthalate or another
suitable material for the application. An example of a film sheet
that is suitable for the second layer is Teonex.RTM. available from
Teijin DuPont Films of Tokyo, Japan. Other materials suitable for
the second layer 20 include but are not limited to polyethylene
terephthalate, aramid paper, aramid fiber, dacron,
polyetheretherketone, or a polyimide, such as
poly(meta-phenyleneisophthalamide). The thickness of the second
layer 20 is from about 0.025 mm to about 0.51 mm.
[0017] The second layer 20, when embodied as a polyethylene
naphthalate film, satisfies the requirements of a 180(H) class
material in accordance with Underwriters Laboratories, Inc. (UL)
Standards. However, the addition of the first and third layers 10,
30 of glass fiber act as a thermal shield, allowing the composite
insulation 50 to operate at a higher UL thermal class of 200(N) in
accordance with Table 4.2 of the UL 1446 standard.
[0018] The first and third layers 10, 30 are bonded to the second
layer 20 using a thin resin solution such as a polyesterimide. The
first and third layers 10, 30 are saturated with the thin resin
solution and pressed against opposing sides of the second layer 20,
respectively. The desired dry thickness of the thin resin solution
after bonding is complete is from about 0.012 mm to about 0.26 mm,
however, the thickness may vary outside of the aforementioned range
depending on the application.
[0019] The first and third layers 10, 30 are adhered to the second
layer 20 using a dielectric insulation lamination machine under
high pressure and temperature to form a sheet of composite
insulation 50. The high temperature and pressure conditions that
are present during the lamination process allow the thin resin
solution to cure and bind the first and third layers 10, 30 to the
second layer 20.
[0020] The resulting composite insulation 50 has sufficient
flexibility to allow formation into a roll for storage or
transport. The composite insulation 50 is unrolled and cut to a
predetermined size for the application following the lamination
process. Alternatively, the first, second, and third layers 10, 20,
30, are each pre-cut to a predetermined length prior to entering
the lamination machine, so that a sheet of composite insulation 50
having the desired size is produced following lamination.
[0021] Further, the composite insulation 50 has application in
transformers wherein the thermal and dielectric withstand of a
220(R) insulation system is required. The glass fibers of the first
and third layers 10, 30, as well as the second layer 20 of thin
film may be provided in a greater thickness than mentioned
previously to achieve a dielectric strength at a higher end of a
transformer operating range, such as a temperature of 200 degrees
Celsius.
[0022] The open wound or vacuum cast transformer in which the
composite insulation 50 is utilized may be single phase or
poly-phase (e.g., three phases). The transformer has a core formed
of thin, stacked laminations of magnetically permeable material,
such as grain-oriented silicon steel or amorphous metal. The
laminations are typically arranged in stacks such that the core has
at least one leg disposed vertically between a pair of yokes
disposed horizontally. A coil assembly 80 is mounted to each core
leg, and comprises low and high voltage coil windings 66, 24.
[0023] The composite insulation 50 has several applications in open
wound transformers. An open wound transformer has coil windings
that are coated, impregnated or encapsulated with a varnish by
dipping or using a vacuum and pressure application process. The
composite insulation 50 serves as the high/low insulating barrier
60 between a low voltage coil winding 66 and a high voltage coil
winding 24, layer insulation in an open wound transformer utilizing
wide sheet conductor in the low voltage coil winding 24 and/or
insulation wrap for a high voltage conductor wire in an open wound
transformer.
[0024] Referring now to FIG. 2, the composite insulation 50 is
embodied as a high/low barrier, between the high and low voltage
coil windings 24, 66 in a transformer coil assembly 80. The
composite insulation 50 is embodied as a sheet cut to a
predetermined length and formed around the low voltage coil winding
66. The width of the sheet used to form the high/low barrier is
approximately 1.22 meters although other widths may be used
depending on the application. The thickness of the composite
insulation 50 is dependent on the rating of the transformer.
[0025] The sheet of composite insulation 50 used to form the
high/low barrier may be secured together at first and second ends
using a glass tape or other dielectric tape. Alternatively, the
sheet of composite insulation 50 may be wrapped around the low
voltage winding in one or more successive layers of composite
insulation 50 before the insulation is secured by dielectric tape
or another means. The high voltage coil winding 24 is then
installed over the high/low barrier, so that a first layer 10 of
the high/low barrier is in contact with the low voltage coil
winding 66 and a third layer 30 of the high/low barrier is in
contact with the high voltage coil winding 24.
[0026] In an embodiment having a high voltage coil winding 24
formed from a disc wound high voltage conductor, the high/low
barrier may include a comb structure (not shown). The comb
structure is formed from the composite insulation 50 into the
desired shape. If comb structures are provided, the high voltage
conductor wire (wrapped in composite insulation 50) is wound
through a circumferentially-arranged series of notches or gaps
formed by teeth (not shown) of the comb structures, wherein each
gap is formed between a pair of adjacent teeth in a comb structure.
Further, spacers formed from the composite insulation 50 may be
placed within the gaps formed by the comb structures.
[0027] The composite insulation 50 has application in a wrap for
high voltage rectangular conductor wire made of copper or aluminum
in an open wound transformer. An open wound transformer has coil
windings that are coated, impregnated or encapsulated with a
varnish by dipping or using a vacuuming and pressure application
process. In that same embodiment, the thickness of the composite
insulation 50 surrounding the rectangular conductor wire is from
about 0.038 mm to about 0.077 mm. The composite insulation 50 is
compatible as a wrap for narrow sheet, strip or foil conductors
that are disc-wound or wound by other methods known in the art and
suitable for the application. The composite insulation 50
encompasses an entire outside surface of the high voltage
rectangular conductor wire.
[0028] The composite insulation 50 has application to open wound
and vacuum cast transformers as wide sheet composite insulation 50
in the low voltage coil winding 66. The width of the sheet used to
form the wide sheet composite insulation 50 is approximately 1.22
meters although other widths may be used depending on the
application.
[0029] The composite insulation 50 is used to shield successive
adjacent layers of low voltage wide sheet conductor from one
another. In that same embodiment, the composite insulation 50
layers are alternated with or sandwiched between successive layers
of sheet conductor material such as copper or aluminum conductor
sheeting as the coil is wound. The low voltage coil 66 may be wound
on a mandrel and/or standard coil forming machine. As the low
voltage coil 66 is being wound, ducts formed from the composite
insulation 50 may be placed between successive layers of sheet
conductor material, in the manner described in U.S. Pat. No.
7,023,312 to Lanoue et al., the entire contents of which is hereby
incorporated by reference in its entirety. It should be understood
that when the composite insulation 50 is embodied as ducts, combs,
or spacers, the thickness of the composite insulation 50 will vary
according to the application.
[0030] The composite insulation 50 is also used in vacuum cast high
voltage coils as narrow sheet insulation. Vacuum cast transformers
have coil windings that are cast with a resin in a mold under a
vacuum. In that same embodiment, the composite insulation 50 is
compatible with narrow sheet conductors that require a thermal
withstand of at least 220 degrees Celsius during operation of the
transformer. The composite insulation 50 used to wrap the narrow
sheet conductor has a thickness of from about 0.05 mm to about 0.09
mm. The narrow sheet conductor may be wound in a foil or disc
fashion.
[0031] The composite insulation 50 has various applications in
motors and generators, including but not limited to wrap or layer
insulation for rotor and/or stator windings, rotor slot insulation,
and corner insulation. The composite insulation 50 may also be
provided in strips, stator wedges, or other embodiments to damp
undesired motor vibrations. An example of a motor in which the
composite insulation 50 has application is a General Purpose AC
Motor, Catalog number M3353, available from Baldor Electric Company
of Fort Smith, Ark.
[0032] Referring now to FIG. 3, an exemplary motor 16 that may
utilize the composite insulation 50 is shown. The motor 16 has a
stator assembly 170 and a rotor assembly 100. The stator assembly
170 has conductor windings 90 that are wrapped in composite
insulation 50. In one embodiment, the wrap for the conductor
windings 90 is from about 0.038 mm to about 0.077 mm thick. The
composite insulation 50 may be utilized in the stator assembly 170
wherein the composite insulation 50 is embodied as a wedge placed
in gaps 58 between stator poles 56 and adjacent conductor windings
90.
[0033] Alternatively, the composite insulation 50 may be utilized
in the rotor assembly 100 between rotor poles 112 and adjacent
conductor windings 90 as a wedge. Another use for the composite
insulation 50 is between motor 16 housing surfaces 52, 110 and the
stator assembly 170 and/or rotor assembly 100, respectively.
[0034] While the present application illustrates various
embodiments of composite electrical insulation 50, and while these
embodiments have been described in some detail, it is not the
intention of the applicant to restrict or in any way limit the
scope of the appended claims to such detail. Additional advantages
and modifications will readily appear to those skilled in the art.
Therefore, the invention, in its broader aspects, is not limited to
the specific details, the representative embodiments, and
illustrative examples shown and described. Accordingly, departures
may be made from such details without departing from the spirit or
scope of the applicant's general inventive concept.
* * * * *